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DEFINITIONS
This source file includes following definitions.
- verify_iovec
- memcpy_toiovec
- memcpy_fromiovec
- memcpy_fromiovecend
- csum_partial_copy_fromiovecend
/*
* iovec manipulation routines.
*
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Fixes:
* Andrew Lunn : Errors in iovec copying.
* Pedro Roque : Added memcpy_fromiovecend and
* csum_..._fromiovecend.
* Andi Kleen : fixed error handling for 2.1
* Alexey Kuznetsov: 2.1 optimisations
* Andi Kleen : Fix csum*fromiovecend for IPv6.
*/
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/net.h>
#include <linux/in6.h>
#include <asm/uaccess.h>
#include <asm/byteorder.h>
#include <net/checksum.h>
#include <net/sock.h>
/*
* Verify iovec. The caller must ensure that the iovec is big enough
* to hold the message iovec.
*
* Save time not doing access_ok. copy_*_user will make this work
* in any case.
*/
int verify_iovec(struct msghdr *m, struct iovec *iov, struct sockaddr *address, int mode)
{
int size, err, ct;
if (m->msg_namelen) {
if (mode == VERIFY_READ) {
err = move_addr_to_kernel(m->msg_name, m->msg_namelen,
address);
if (err < 0)
return err;
}
m->msg_name = address;
} else {
m->msg_name = NULL;
}
size = m->msg_iovlen * sizeof(struct iovec);
if (copy_from_user(iov, m->msg_iov, size))
return -EFAULT;
m->msg_iov = iov;
err = 0;
for (ct = 0; ct < m->msg_iovlen; ct++) {
err += iov[ct].iov_len;
/*
* Goal is not to verify user data, but to prevent returning
* negative value, which is interpreted as errno.
* Overflow is still possible, but it is harmless.
*/
if (err < 0)
return -EMSGSIZE;
}
return err;
}
/*
* Copy kernel to iovec. Returns -EFAULT on error.
*
* Note: this modifies the original iovec.
*/
int memcpy_toiovec(struct iovec *iov, unsigned char *kdata, int len)
{
while (len > 0) {
if (iov->iov_len) {
int copy = min_t(unsigned int, iov->iov_len, len);
if (copy_to_user(iov->iov_base, kdata, copy))
return -EFAULT;
kdata += copy;
len -= copy;
iov->iov_len -= copy;
iov->iov_base += copy;
}
iov++;
}
return 0;
}
/*
* Copy iovec to kernel. Returns -EFAULT on error.
*
* Note: this modifies the original iovec.
*/
int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len)
{
while (len > 0) {
if (iov->iov_len) {
int copy = min_t(unsigned int, len, iov->iov_len);
if (copy_from_user(kdata, iov->iov_base, copy))
return -EFAULT;
len -= copy;
kdata += copy;
iov->iov_base += copy;
iov->iov_len -= copy;
}
iov++;
}
return 0;
}
/*
* For use with ip_build_xmit
*/
int memcpy_fromiovecend(unsigned char *kdata, struct iovec *iov, int offset,
int len)
{
/* Skip over the finished iovecs */
while (offset >= iov->iov_len) {
offset -= iov->iov_len;
iov++;
}
while (len > 0) {
u8 __user *base = iov->iov_base + offset;
int copy = min_t(unsigned int, len, iov->iov_len - offset);
offset = 0;
if (copy_from_user(kdata, base, copy))
return -EFAULT;
len -= copy;
kdata += copy;
iov++;
}
return 0;
}
/*
* And now for the all-in-one: copy and checksum from a user iovec
* directly to a datagram
* Calls to csum_partial but the last must be in 32 bit chunks
*
* ip_build_xmit must ensure that when fragmenting only the last
* call to this function will be unaligned also.
*/
int csum_partial_copy_fromiovecend(unsigned char *kdata, struct iovec *iov,
int offset, unsigned int len, __wsum *csump)
{
__wsum csum = *csump;
int partial_cnt = 0, err = 0;
/* Skip over the finished iovecs */
while (offset >= iov->iov_len) {
offset -= iov->iov_len;
iov++;
}
while (len > 0) {
u8 __user *base = iov->iov_base + offset;
int copy = min_t(unsigned int, len, iov->iov_len - offset);
offset = 0;
/* There is a remnant from previous iov. */
if (partial_cnt) {
int par_len = 4 - partial_cnt;
/* iov component is too short ... */
if (par_len > copy) {
if (copy_from_user(kdata, base, copy))
goto out_fault;
kdata += copy;
base += copy;
partial_cnt += copy;
len -= copy;
iov++;
if (len)
continue;
*csump = csum_partial(kdata - partial_cnt,
partial_cnt, csum);
goto out;
}
if (copy_from_user(kdata, base, par_len))
goto out_fault;
csum = csum_partial(kdata - partial_cnt, 4, csum);
kdata += par_len;
base += par_len;
copy -= par_len;
len -= par_len;
partial_cnt = 0;
}
if (len > copy) {
partial_cnt = copy % 4;
if (partial_cnt) {
copy -= partial_cnt;
if (copy_from_user(kdata + copy, base + copy,
partial_cnt))
goto out_fault;
}
}
if (copy) {
csum = csum_and_copy_from_user(base, kdata, copy,
csum, &err);
if (err)
goto out;
}
len -= copy + partial_cnt;
kdata += copy + partial_cnt;
iov++;
}
*csump = csum;
out:
return err;
out_fault:
err = -EFAULT;
goto out;
}
EXPORT_SYMBOL(csum_partial_copy_fromiovecend);
EXPORT_SYMBOL(memcpy_fromiovec);
EXPORT_SYMBOL(memcpy_fromiovecend);
EXPORT_SYMBOL(memcpy_toiovec);